1. Field of the Invention
The present invention relates to heat insulating covers and more particularly pertains to an improved heat insulating blanket which may be utilized as a bed cover or sleeping bag.
2. Description of the Prior Art
The use of heat insulating bed covers is known in the prior art. Typical examples of well designed thermal insulating blankets are to be found in U.S. Pat. No. 4,915,998, which issued to Parenti, Jr. et al. on Apr. 10, 1990, and U.S. Pat. No. 4,927,705, which issued to Syme et al. on May 22, 1990. The Parenti, Jr. et al. patent discloses a thermal insulation blanket which utilizes a plurality of goldized film layers having interleaved ceramic fiberglass cloth layers, thereby to provide insulation against radiated heat loss in a space environment. Adjacent to the goldized layer is a felt or foam mat which provides insulation against conduction or convection heat loss in the ambient environment. As can be appreciated, this patent clearly teaches the use of multiple layers of various materials to achieve a heat insulating effect.
By the same token, the Syme et al. patent discloses an insulating laminate which, in part, discloses a compressible polyester blanket bonded directly at one surface to a polymer surface of a vapor barrier formed by a metallized moisture and impermeable, polymer film. Again there is provided the teaching of using multiple layers of different materials to achieve a heat insulating effect. However, both of these above-described patents do not take into account different heat insulating requirements of a user's body. More specifically, the body heat distribution for most people is greater in an upper area of their body and less in their legs and feet, whereby it might be desireable to provide an insulating cover that provides variable degrees of insulation over a human body. As such, it would appear that there exists a continuing need for new and improved heat insulating covers which could function to overcome this uneven heat distribution problem and in this regard, the present invention substantially fulfills this need.